This invention relates to a method of manufacturing a multi-stylus recording head suitable for an electrostatic recording device of wide range scan type, and an apparatus for practicing the method.
A multi-stylus recording head of an electrostatic recording device comprises: a recording electrode array including recording electrodes arranged at extremely small intervals, or such a recording electrode array and a control electrode array arranged along the recording electrode array. In order to simplify a drive circuit for the recording electrodes, the recording electrode array is divided in a plurality of blocks, which are connected to drive circuits. Generally, in the multi-stylus recording head having M x N recording electrodes, the recording electrodes are divided into N groups (blocks) each having M recording electrodes. The terms "M" and "N" are used in place of numerical values. One recording electrode is selected from each group of recording electrodes, and the N recording electrodes thus selected are bundled, so that M bundles of recording electrodes are formed. The M bundles of recording electrodes thus formed are connected to a wiring terminal board.
In one example of a conventional method of manufacturing a multi-stylus recording head, spiral grooves are formed in the cylindrical surface of a drum, a wire providing recording electrodes (hereinafter referred to merely as "a wire" or "an electrode wire", when applicable) is wound in the grooves a predetermined number of turns, the wires thus wound are fixed along the generating line of the drum and then suitably cut to provide a head surface. The assembly of the wires thus cut is removed from the drum and control electrode arrays are arranged on both sides thereof, to form a head element. The electrode wires forming the recording electrode array are connected to a wiring terminal board as follows: One wire is selected from each group of wires in such a manner that the wires thus selected are equal in positional relation to one another. The wires thus selected are bundled to form a bundle of wires. The bundles of wires thus formed are connected to the wiring terminal board In the method, one electrode wire is wound on the drum in such a manner that the wires thus wound are aligned with one another. Therefore, the method is advantageous in that the wire aligning speed (or wire supplying speed) is high. However, the method suffers from difficulties that, since the wires selected from the groups of wires one per group are manually bundled, the wire bundling operation is low in work efficiency, and the wires may be broken or may be connected incorrectly, and therefore the resultant product is low in reliability.
In order to improve the work efficiency and the reliability, a method has been proposed, for instance, by Japanese Patent Application Publication No. 25390/1981. In the method, a number of electrodes wires which are equal in positional relation to one another in the groups of wires are held mechanically uniformly tensioned, and are then bonded together with adhesive tape. Both end portions of the wires, after being cut, are bundled and temporarily connected to V-shaped grooves of a printed circuit board. The above-described operations are repeatedly carried out as many times as the number of the groups. In the method, the electrode wires are bundled every groups, which eliminates the above-described difficulties that the wire are connected erroneously, and the resultant product is low in reliability.
However, the method is also disadvantageous in the following points: It needs a number of manufacturing means such as means for supplying a number of electrode wires, means for tensioning these wires uniformly, means for cutting the wires at both ends, and accordingly, an apparatus for practicing the method is unavoidably intricate in construction and bulky in size. Furthermore, it will take lots of time and labor to supply a number of thin copper electrode wires and to align them. Therefore, the method still suffer from problems to be solved technically.